TW variables have a scope and can be “stacked”
The code snippets below only make sense, if you try them yourself!
There are several things in TW that change the currentTiddler variable
- Directly setting currentTiddler with a $set or $let widget.
- Using a $list widget to enumerate the outputs of a filter.
- Transcluding another tiddler with the {{curly braces}} syntax.
- Using a $tiddler widget.
Set-widget
As I wrote. Variables have a scope. They are valid inside the widget they are defined in.
Procedures and macro definitions are special cases of set-widgets.
Their scope is the whole tiddler.
title: procedures-are-variables
\procedure test() abc
\procedure test() xyz
```
<<test>> ... Will be xyz
```
<<test>> ... Will be xyz
So the last one wins. The above code is a “shortcut for”
<$set name=test value=abc>
<$set name=test value=xyz>
<<test>>
</$set>
</$set>
Try this:
<$set name=test value=abc>
<<test>>
<$set name=test value=xyz>
<<test>>
</$set>
</$set>
list-widget
Let’s say I want to create a list of tiddler links, that use the name of the tiddler the code lives in and add “a”, “b” and “c” at the end.
title: myTemplate
\function concat() [<currentTiddler>] [<title>] +[join[-]]
<$list filter="a b c" variable="title">
<$link to=<<concat>> /><br>
</$list>
By default the list-widget would “overwrite” the currentTiddler variable, that’s why we can provide a new variable name. In this case title
- The list-widget iterates over a, b, c and sets the title variable.
- The currentTiddler stays the same.
The currentTiddler variable is the tiddler-title, the code lives in.
The concat function can be implemented in several more ways, depending on the usecase.
Transclusion
If you create a new tiddler named: test … You can play with templates.
- The first transclusion will set the currentTiddler variable to
myTemplate - The second transclusion will pass the currentTiddler variable on to the template
- The third example passe the name “xxx” to the template, which will be used as currenTiddler
title: test
{{myTemplate}}
---
{{||myTemplate}}
---
{{xxx||myTemplate}}
Docs about transclusion: https://tiddlywiki.com/#Transclusion%20in%20WikiText
About your code
First things first. Syntax.
There is a syntax error here. It’s not possible to have spaces between = and <<currentTiddler>>
- In the example below the tiddler title is BLARGH
- When a tiddler is rendered in the story, the UI defines the
currentTiddlervariable and sets it to the tiddler-title, so it can be used in the tiddler body text.
- When a tiddler is rendered in the story, the UI defines the
- Then the set-widget form your code will set the
thisvariable to<<currentTiddler>>which isBLARGHas defined above.- IMO you got that right, but IMO there was a syntax problem
- Then the contains-operator will list all tiddlers that have a field named:
worshipsGod- Internally the filter is automatically expanded to
[all[tiddlers]contains:worshipsGod . . . - Then it will compare the value of
worshipsGodfield with the value of the variable<this>
- Internally the filter is automatically expanded to
title: BLARGH
<$set name="this" value=<<currentTiddler>>>
BLARGH should be 'this' of course.
<$list filter="[contains:worshipsGod<this>!sort[at]]">
<<currentTiddler>><br>
</$list>
</$set>
According to the documentation, the list-widget will use the variable <<currentTiddler>> inside its body.
But
That can be changed with the “variable” parameter. So you can choose any name, that fits helps you to make the code more understandable.
<$list filter="[contains:worshipsGod<this>!sort[at]]" variable="name-of-god">
<<name-of-god>><br>
</$list>
You can use the attached JSON tiddlers and play with the examples above.
Playing around with the stuff should make things clearer
Hope that helps
Have fun!
mario
variable-scopes.json (1.1 KB)